Preparation of amino-acids containing imino-groups



United States Pmtto PREPARATION OF AMINO-ACIDS CONTAINING IMINO-GROUI'S I Rudolf Lotz, Klingenberg (Main), Germany, assignor to Vereinigte Glanzstolf-Fabrikeu A. G., Wuppertal- Elberfeld, Germany i No Drawing. Application April 16, 1953, Serial No. 349,313

Claims priority, application Germany April 22, 1952 2 Claims. (Cl. 260-534) This invention relates to amino-acids, and more particularly to methods of preparing amino-acids containing imino-groups, and the compounds thus prepared.

It is an object of this invention to provide a method of preparing novel amino-acids containing in their chain two imino-groups separated from one another.

It is another object of this invention to provide novel amino-acids the chain of which contains two mutually separated imino-groups, and which lend themselves to a use as intermediate products, in the production of plastics, textile auxiliaries and softening agents.

Other objects, and the manner in which the same are attained, will become apparent as this specification proceeds.

The invention contemplates preparing amino-acids containing two imino-groups separated from one another in the chain and corresponding to the following general formula:

wherein R represents H, CH3, Cl, -NHz or -CaH5. The novel amino-acids according to the invention are prepared from a starting material consisting of cyclic compounds having the following constitution:

crrworrrco-Nrr R HN H CHrCHa-COQQ? wherein R represents H, CH3, -Cl, NHz or -CsH5. The cyclic compounds forming the starting material for the method of this invention are obtained if in accordance with the process disclosed in my copending application for U. S. Letters Patent Serial No. 299,734, filed July 18, 1952, unilaterally aminated methylene-bis-ch1oropropionic acid amides of the formula are forced to split olf, quantitatively, HCl. In the course of this process, the cyclic compounds forming the starting material for the present invention and illustrated above by their formula, are obtained along with the polycondensation products of linear structure the preparation of which is the gist of the aforenoted copending application Serial No. 299,734.

Proceeding from the cyclic compounds forming the starting material for the present invention, the present method effects a ring cleavage attacking one of the CO-NH linkages, in order to arrive at the novel amino-acids containing two imino-groups aimed at by the invention.

It is recommended to effect this ring cleavage in an alkaline medium and preferably, within the pH-range of from about 8 to about 12 as otherwise, the reaction mechanism does not follow sufiiciently clear lines.

Preferably, therefore, the method of the invention involves dissolving the cyclic starting compound e. g. in a diluted ammonia solution, heating the solution thus obtained with reflux, to a temperature from about 80 C.

, 2,740,812 Patented Apr. 3, 1956 to about 100 C., recovering the sirupy reaction product and cleaning or purifying the same.

The novel amino-acids containing two imino-groups ice ' separated from one another, thus obtained are eminently useful as intermediates in the preparation of plastics, textile auxiliaries and softeners.

The method of preparing these novel amino-acids according to the invention, results in yields exceeding per cent.

The invention-will be more fully described by reference to the following specific examples. It should be understood, however, that the examples are given by way of illustration only and that the invention is not to be limited by the details set forth therein.

Example I 5 g. of the cyclic compound CqI-IrsOzNs corresponding to the structural formula HN CH2 and having a well defined melting point at 171 C., is obtained at a yield somewhat in excess of 80 per cent of the theoretical yield.

Example 11 The method corresponds to that described with reference to Example I, except that as the starting material, the following substituted ring-compound is used:

which has a melting point of 65 C. On completion of the treatment set forth with reference to Example I, the novel substituted amino-acid corresponding to the formula is obtained, at a yield of 80 per cent of the theoretical yield; this compound has a melting point of 128 C.

While I have disclosed the preferred embodiments of my invention, and the preferred modes of carrying it into effect, it will be readily apparent to those skilled in the art that the invention as illustrated in the foregoing specification, is susceptible to numerous variations without departure from the spirit of the invention or sacrifice of the advantages thereof. Accordingly, the scope of the invention is to be understood as limited solely by the appended claims.

I claim:

1. The method of preparing amino-acids containing imino-groups, of the general formula wherein R represents "H, --CHa, -Cl, --NH:, --CsI-Is,

3 comprising heating cyclic compounds of the general formula CH1'CH1-CO-NH\R H-N H CHz-CHz-CO-NH wherein R represents 'H, --CH3, --Cl, --NH2, -CsH5 to a temperaturefrom about 80 to about 100 C., in alkaline solution.

2. The method of preparing amino-acids containing 10 imino-groups, of the general formula wherein R represents -H, CH3, Cl, NHz, comprisingrheating cyclic compounds .of the general formula OHrCHa-CO'NH R HN\ CB.

CHa-CHrC O-NH wherein R represents -'H, -CH3, CI, NH2, CaI-I5 to a temperature from about 80 to about 100 C., in alkaline solution of a pH of from about 8 to about 12.

No references cited. 

1. THE METHOD OF PREPARING AMINO-ACIDS CONTAINING IMINO-GROUPS OF THE GENERAL FORMULA 